1 /*
2  * IEEE 802.11.
3  */
4 
5 #include <u.h>
6 #include <libc.h>
7 #include <ip.h>
8 #include "dat.h"
9 #include "protos.h"
10 
11 enum
12 {
13 	Tmgmt = 0,
14 	Tctl,
15 	Tdata,
16 
17 	CtlPoll = 0xA,
18 	CtlRts,
19 	CtlCts,
20 	CtlAck,
21 	CtlCfEnd,
22 	CtlCfEndAck,
23 
24 	Data = 0,
25 	DataCfAck,
26 	DataCfPoll,
27 	DataCfAckPoll,
28 	Nodata,
29 	NodataCfAck,
30 	NodataCfPoll,
31 	NodataCfAckPoll,
32 
33 	FlagTods = 0x1,
34 	FlagFromds = 0x2,
35 	FlagMoreflag = 0x4,
36 	FlagRetry = 0x8,
37 	FlagPowerMgmt = 0x10,
38 	FlagMoreData = 0x20,
39 	FlagWep = 0x40,
40 	FlagOrder = 0x80,
41 
42 	ProtoNone = 0,
43 	ProtoLlc,
44 };
45 
46 static Mux p_mux[] =
47 {
48 	{ "llc", ProtoLlc },
49 	{ 0 }
50 };
51 
52 typedef struct Hdr Hdr;
53 struct Hdr
54 {
55 	uchar vers;
56 	uchar type;
57 	uchar subtype;
58 	uchar flags;
59 	ushort dur;
60 	uchar aid;
61 	uchar ra[6];
62 	uchar ta[6];
63 	uchar bssid[6];
64 	uchar sa[6];
65 	uchar da[6];
66 	ushort seq;
67 	int proto;
68 	int hdrlen;
69 };
70 
71 static int
72 unpackhdr(uchar *p, uchar *ep, Hdr *h)
73 {
74 	if(p+2 > ep)
75 		return -1;
76 	h->vers = p[0]&3;
77 	if(h->vers != 0){
78 		h->hdrlen = 2;
79 		return -1;
80 	}
81 	h->type = (p[0]>>2)&3;
82 	h->subtype = (p[0]>>4)&15;
83 	h->flags = p[1];
84 	h->hdrlen = 2;
85 
86 	if(h->vers != 0)
87 		return 0;
88 
89 	switch(h->type){
90 	case Tmgmt:
91 		// fc dur da sa bssid seq
92 		if(p+2+2+6+6+6+2 > ep)
93 			return -1;
94 		h->hdrlen = 24;
95 		h->dur = LittleS(p+2);
96 		memmove(h->da, p+4, 6);
97 		memmove(h->sa, p+10, 6);
98 		memmove(h->bssid, p+16, 6);
99 		h->seq = LittleS(p+22);
100 		break;
101 
102 	case Tctl:
103 		switch(h->subtype){
104 		case CtlPoll:
105 			// fc aid bssid ta
106 			if(p+2+2+6+6 > ep)
107 				return -1;
108 			h->hdrlen = 16;
109 			h->aid = LittleS(p+2);
110 			memmove(h->bssid, p+4, 6);
111 			memmove(h->ta, p+10, 6);
112 			break;
113 
114 		case CtlRts:
115 			// fc dur ra ta
116 			if(p+2+2+6+6 > ep)
117 				return -1;
118 			h->hdrlen = 16;
119 			h->dur = LittleS(p+2);
120 			memmove(h->ra, p+4, 6);
121 			memmove(h->ta, p+10, 6);
122 			break;
123 
124 		case CtlCts:
125 		case CtlAck:
126 			// fc dur ra
127 			if(p+2+2+6 > ep)
128 				return -1;
129 			h->hdrlen = 10;
130 			h->dur = LittleS(p+2);
131 			memmove(h->ra, p+4, 6);
132 			break;
133 
134 		case CtlCfEnd:
135 		case CtlCfEndAck:
136 			// fc dur ra bssid
137 			if(p+2+2+6+6 > ep)
138 				return -1;
139 			h->hdrlen = 16;
140 			h->dur = LittleS(p+2);
141 			memmove(h->ra, p+4, 6);
142 			memmove(h->bssid, p+10, 6);
143 			break;
144 		}
145 		break;
146 
147 	case Tdata:
148 		if(p+24 > ep)
149 			return -1;
150 		h->hdrlen = 24;
151 		h->dur = LittleS(p+2);	// ??? maybe
152 		// Also, what is at p+22?
153 
154 		switch(h->flags&(FlagFromds|FlagTods)){
155 		case 0:
156 			memmove(h->da, p+4, 6);
157 			memmove(h->sa, p+10, 6);
158 			memmove(h->bssid, p+16, 6);
159 			break;
160 		case FlagFromds:
161 			memmove(h->da, p+4, 6);
162 			memmove(h->bssid, p+10, 6);
163 			memmove(h->sa, p+16, 6);
164 			break;
165 		case FlagTods:
166 			memmove(h->bssid, p+4, 6);
167 			memmove(h->sa, p+10, 6);
168 			memmove(h->da, p+16, 6);
169 			break;
170 		case FlagFromds|FlagTods:
171 			if(p+30 > ep)
172 				return -1;
173 			h->hdrlen = 30;
174 			memmove(h->ra, p+4, 6);
175 			memmove(h->ta, p+10, 6);
176 			memmove(h->da, p+16, 6);
177 			memmove(h->sa, p+24, 6);	// 24 sic
178 			break;
179 		}
180 		p += h->hdrlen;
181 		h->proto = ProtoNone;
182 		if(!(h->flags&FlagWep))
183 			h->proto = ProtoLlc;
184 		break;
185 	}
186 	return 0;
187 }
188 
189 enum
190 {
191 	Os,
192 	Od,
193 	Ot,
194 	Or,
195 	Obssid,
196 	Oa,
197 	Opr,
198 };
199 
200 static Field p_fields[] =
201 {
202 	{ "s",	Fether,	Os,	"source address" },
203 	{ "d",	Fether,	Od,	"destination address" },
204 	{ "t",	Fether,	Ot,	"transmit address" },
205 	{ "r",	Fether,	Or,	"receive address" },
206 	{ "bssid", Fether,	Obssid, "bssid address" },
207 	{ "a",	Fether,	Oa,	"any address" },
208 	{ "sd",	Fether,	Oa,	"source|destination address" },
209 	{ 0 }
210 };
211 
212 static void
213 p_compile(Filter *f)
214 {
215 	Mux *m;
216 
217 	if(f->op == '='){
218 		compile_cmp(p80211.name, f, p_fields);
219 		return;
220 	}
221 	if(strcmp(f->s, "mgmt") == 0){
222 		f->pr = &p80211;
223 		f->ulv = Tmgmt;
224 		f->subop = Ot;
225 		return;
226 	}
227 	if(strcmp(f->s, "ctl") == 0){
228 		f->pr = &p80211;
229 		f->ulv = Tctl;
230 		f->subop = Ot;
231 		return;
232 	}
233 	if(strcmp(f->s, "data") == 0){
234 		f->pr = &p80211;
235 		f->ulv = Tdata;
236 		f->subop = Ot;
237 		return;
238 	}
239 	for(m = p_mux; m->name != nil; m++){
240 		if(strcmp(f->s, m->name) == 0){
241 			f->pr = m->pr;
242 			f->ulv = m->val;
243 			f->subop = Opr;
244 			return;
245 		}
246 	}
247 	sysfatal("unknown 802.11 field or protocol: %s", f->s);
248 }
249 
250 static int
251 p_filter(Filter *f, Msg *m)
252 {
253 	Hdr h;
254 
255 	memset(&h, 0, sizeof h);
256 	if(unpackhdr(m->ps, m->pe, &h) < 0)
257 		return 0;
258 	m->ps += h.hdrlen;
259 
260 	switch(f->subop){
261 	case Os:
262 		return memcmp(h.sa, f->a, 6) == 0;
263 	case Od:
264 		return memcmp(h.da, f->a, 6) == 0;
265 	case Ot:
266 		return memcmp(h.ta, f->a, 6) == 0;
267 	case Or:
268 		return memcmp(h.ra, f->a, 6) == 0;
269 	case Obssid:
270 		return memcmp(h.bssid, f->a, 6) == 0;
271 	case Oa:
272 		return memcmp(h.sa, f->a, 6) == 0
273 			|| memcmp(h.da, f->a, 6) == 0
274 			|| memcmp(h.ta, f->a, 6) == 0
275 			|| memcmp(h.ra, f->a, 6) == 0
276 			|| memcmp(h.bssid, f->a, 6) == 0;
277 	case Opr:
278 		return h.proto == f->ulv;
279 	}
280 	return 0;
281 }
282 
283 static int
284 p_seprint(Msg *m)
285 {
286 	Hdr h;
287 
288 	memset(&h, 0, sizeof h);
289 	if(unpackhdr(m->ps, m->pe, &h) < 0)
290 		return -1;
291 
292 	m->pr = &dump;
293 	m->p = seprint(m->p, m->e, "fc=%02x flags=%02x ", m->ps[0], m->ps[1]);
294 	switch(h.type){
295 	case Tmgmt:
296 		m->p = seprint(m->p, m->e, "mgmt dur=%d d=%E s=%E bssid=%E seq=%d",
297 			h.dur, h.da, h.sa, h.bssid, h.seq);
298 		break;
299 	case Tctl:
300 		switch(h.subtype){
301 		case CtlPoll:
302 			m->p = seprint(m->p, m->e, "ctl poll aid=%d bssid=%E t=%E",
303 				h.aid, h.bssid, h.ta);
304 			break;
305 		case CtlRts:
306 			m->p = seprint(m->p, m->e, "ctl rts dur=%d r=%E t=%E",
307 				h.dur, h.ra, h.ta);
308 			break;
309 		case CtlCts:
310 			m->p = seprint(m->p, m->e, "ctl cts dur=%d r=%E",
311 				h.dur, h.ra);
312 			break;
313 		case CtlAck:
314 			m->p = seprint(m->p, m->e, "ctl ack dur=%d r=%E",
315 				h.dur, h.ra);
316 			break;
317 		case CtlCfEnd:
318 			m->p = seprint(m->p, m->e, "ctl cf end dur=%d r=%E bssid=%E",
319 				h.dur, h.ra, h.bssid);
320 			break;
321 		case CtlCfEndAck:
322 			m->p = seprint(m->p, m->e, "ctl cf end ack dur=%d r=%E bssid=%E",
323 				h.dur, h.ra, h.bssid);
324 			break;
325 		default:
326 			m->p = seprint(m->p, m->e, "ctl %.*H", m->ps, h.hdrlen);
327 			break;
328 		}
329 		break;
330 	case Tdata:
331 		switch(h.flags&(FlagFromds|FlagTods)){
332 		case 0:
333 			m->p = seprint(m->p, m->e, "data d=%E s=%E bssid=%E",
334 				h.da, h.sa, h.bssid);
335 			break;
336 		case FlagFromds:
337 			m->p = seprint(m->p, m->e, "data fds d=%E bssid=%E s=%E",
338 				h.da, h.bssid, h.sa);
339 			break;
340 		case FlagTods:
341 			m->p = seprint(m->p, m->e, "data tds bssid=%E s=%E d=%E",
342 				h.bssid, h.sa, h.da);
343 			break;
344 		case FlagFromds|FlagTods:
345 			m->p = seprint(m->p, m->e, "data fds tds r=%E t=%E d=%E s=%E",
346 				h.ra, h.ta, h.da, h.sa);
347 			break;
348 		}
349 		if(!(h.flags&FlagWep))
350 			m->pr = &llc;
351 		break;
352 	}
353 	m->ps += h.hdrlen;
354 	return 0;
355 }
356 
357 Proto p80211 =
358 {
359 	"802.11",
360 	p_compile,
361 	p_filter,
362 	p_seprint,
363 	p_mux,
364 	nil,
365 	nil,
366 	defaultframer
367 };